Control valve trim assembly having a cage with diamond-shaped openings

ABSTRACT

A fluid valve includes a valve body having a fluid inlet and a fluid outlet connected by a fluid passageway. A valve seat is disposed within the fluid passageway. A fluid control member is movably disposed within the fluid passageway, the fluid control member cooperating with a trim assembly to control fluid flow through the fluid passageway. The trim assembly includes a cage having a plurality of diamond-shaped openings disposed in a wall thereof.

RELATED PATENT APPLICATIONS

This patent application claims priority benefit of U.S. ProvisionalPatent Application No. 61/894,236, filed Oct. 22, 2013; the entirety ofwhich is incorporated by reference herein.

FIELD OF THE DISCLOSURE

The invention generally relates to control valves including a trimassembly having a high flow region and more specifically to trimassemblies including a cage having diamond-shaped openings.

BACKGROUND

Fluid valves control the flow of fluid from one location to another.When the fluid valve is in a closed position, high pressure fluid on oneside is prevented from flowing to a lower pressure location on the otherside of the valve. Often fluid valves contain a movable fluid controlmember and a seat of some sort that cooperates with the fluid controlmember to control fluid flow through the valve. In some cases it may bedesirable to characterize fluid as it flows through the valve, forexample, to reduce noise. In these cases, a trim assembly may be usedthat includes a cage with a plurality of openings. The openings may besized and shaped to characterize fluid flow through the trim assembly.During normal operations, system demand may require limited movement ofthe fluid control member. However, during high demand or surgeoperations, the cage openings may restrict fluid flow through the trimassembly to a level less than what is required by the surge conditionbecause the cage openings simply do not have sufficient flow capacity tomeet the need of the surge operation.

SUMMARY OF THE DISCLOSURE

A fluid valve includes a valve body having a fluid inlet and a fluidoutlet connected by a fluid passageway. A trim assembly is disposedwithin the fluid passageway, the trim assembly including a cage and avalve seat. A fluid control member is movably disposed within the fluidpassageway and within the cage, the fluid control member cooperatingwith the valve seat to control fluid flow through the fluid passageway.The cage includes a plurality of diamond-shaped openings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a control valve having a trimassembly constructed in accordance with the teachings of the disclosure;

FIG. 2 is a close up view of a cage of the trim assembly of FIG. 1;

FIG. 3 is a close up view of an alternate embodiment of the trimassembly of FIG. 1; and

FIG. 4 is a cross-sectional view of the cage of FIG. 3.

DETAILED DESCRIPTION

The trim assemblies described herein advantageously provide largeincreases in flow area with minimal travel of a fluid control element,such as a valve plug. The disclosed trim assemblies may be used asstand-alone trim assemblies, or the disclosed cage openings may becombined with other trim assemblies to produce trim assemblies thatcharacterize fluid flow while having an anti-surge capability. Thedisclosed cage openings improve radial strength of the cage, whichallows the disclosed trim assemblies to be used in high pressure dropoperations, such as compressor anti-surge operations. The disclosed trimassemblies may be particularly useful in sliding stem control valves.

Additionally, the disclosed trim assemblies result in control valvesthat have smaller cages relative to known trim assemblies, and thus thedisclosed trim assemblies may be used in control valves having smallervalve bodies. While the cages are generally smaller than known cages fora given use, the disclosed cages include a high flow capacity regionhaving a rapidly increasing flow area for a given valve plug travel. Asa result, the disclosed trim assemblies are particularly useful intwo-stage trim assemblies where a first stage includes a drilled holepattern that throttles (or characterizes) fluid flow over a normal rangeof demand and a second stage having specially shaped openings or portsto provide a large increase in flow area for minimal increases in valveplug travel to allow rapid increase in fluid flow during high demandsituations.

Turning now to FIG. 1, a control valve 10 includes a valve body 12having a fluid inlet 14 and a fluid outlet 16 connected by a fluidpassageway 18. A trim assembly 20 is disposed within the valve body 12between the fluid inlet 14 and the fluid outlet 16. The trim assembly 20includes a cage 22 and a seat 24. A fluid control member, such as a plug26 is disposed within the cage 22 and the plug 26 interacts with theseat 24 to control fluid flow through the valve body 12. A stem 28 isconnected to the plug 26 at one end and an actuator 30 at another end.The actuator 30 controls movement of the plug 26 within the cage 22.

As illustrated in FIG. 2, one embodiment of a cage 22 includes the seat24 at a first end 32 and an opening 34 at a second end 36. A cage wall38 extends between the first end 32 and the second end 36, the cage wall38 forming a hollow central bore within which the valve plug 26 slidesto control fluid flow through the cage 22. A plurality of cage openings40 is formed in the cage wall 38. The plurality of cage openings 40 mayinclude one or more diamond-shaped openings 42. The diamond-shapedopening 42 may include a first edge 44 and a second edge 46 that form afirst intersection 48. The first edge 44 and the second edge 46 may forma first angle 50 of approximately 30 degrees. Preferably the first angle50 may be in the range of approximately 10 degrees to approximately 80degrees, more preferably between 20 degrees and 60 degrees, and evenmore preferably between 25 degrees and 40 degrees. The first angle 50 inthe disclosed ranges advantageously allow a high density ofdiamond-shaped openings 42 to be located in the cage wall 38.

The diamond-shaped opening 42 may also include a third edge 52 and afourth edge 54 that form a second intersection 56. The secondintersection 56 may include a second angle 58 in the same rangesdescribed above for the first angle 50. A line between the firstintersection 48 and the second intersection 56 defines a longitudinalaxis 60 of the diamond-shaped opening 42. In the embodiment of FIG. 2,the longitudinal axis 60 is oriented substantially parallel to alongitudinal axis 62 of the cage 22. In other embodiments, thelongitudinal axis 60 may be oriented substantially perpendicular to thelongitudinal axis 62 of the cage.

The diamond-shaped opening 42 may optionally include a first flat edge64 connecting the first edge 44 and the third edge 52 and a second flatedge 66 connecting the second edge 46 and the fourth edge 54. When afirst diamond-shaped opening 42′ and a second diamond-shaped opening 42″are located adjacent to one another, the second flat edge 66′ of thefirst diamond-shaped opening 42′ may be located adjacent to the firstflat edge 64″ of the second diamond-shaped opening 42″, and vice versa.As a result, a web 70 may be formed between the individualdiamond-shaped openings 42 in the plurality of diamond-shaped openings40. The web 70 may include a plurality of X-shaped plugs 71 that have afirst leg 72, a second leg 74, a third leg 76, and a fourth leg 78 thatintersect at a center portion 80. The web 70 gives radial strength tothe cage 22 in the region of the plurality of diamond-shaped openings40. In some embodiments, the first leg 72, second leg 74, third leg 76,and fourth leg 78 may have a thickness 79 in the range of approximately1 mm to approximately 25 mm, more preferably in the range ofapproximately 5 mm to approximately 20 mm, and even more preferably inthe range of approximately 10 mm to approximately 20 mm. Thicknesses inthe disclosed ranges result in a nearly optimal tradeoff between radialstrength and increased flow area.

In the embodiment of FIG. 2, the plurality of diamond-shaped openings 40may be separated from the seat 24 by a first distance 82. Similarly, theplurality of diamond-shaped openings 40 may be separated from the secondend 36 of the cage 22 by a second distance 84. The first and seconddistances 82, 84 limit the plurality of openings 40 to a high flowregion 86. In other embodiments, the plurality of diamond shapedopenings 40 may extend completely to the first end 32, the second end34, or both.

As illustrated in FIG. 3, another embodiment of a cage 122 may include aplurality of diamond-shaped openings 40. At least one diamond-shapedopening 142 may be shaped as described above with respect to FIG. 2. Theplurality of diamond-shaped openings 40 produces a high flow region 186.A plurality of flow characterizing openings, such as a plurality ofnoise-attenuating openings 188, may be formed in the cage wall 138. Theplurality of noise-attenuating openings 188 may include one or morecircular openings 190 that characterize fluid flow through the valveduring normal operations. Thus, the plurality of noise-attenuatingopenings 188 produce a flow characterizing region 190. A transitionregion 192 is formed between the high flow region 186 and the flowcharacterizing region 190. During normal operations, fluid may flowthrough the plurality of noise-attenuating openings 188 in the flowcharacterizing region 190. When downstream demand exceeds flow capacityof the flow characterizing region 190, such as during surge operations,the valve plug 26 (FIG. 1) opens sufficiently to allow fluid to beginflowing through the plurality of diamond-shaped openings 140 in the highflow region 186. In some embodiments, portions of the diamond shapedopenings 142 may overlap with portions of the noise-attenuating openings190 in the transition region 192 to produce a smooth transition betweennoise-attenuation (or other flow characterizing) operations and surgeoperations. As described above, the plurality of diamond-shaped openings140 give the cage 122 a high flow capability while preserving radialstrength of the cage 122 for high pressure drop situations.

FIG. 4 is a cross-sectional view of the cage 122 of FIG. 3. Theplurality of diamond-shaped openings 140 are located closer to thesecond end 136 of the cage 122 than the plurality of noise-attenuatingopenings 188. The cage wall 138 includes a cut-out or recessed portion194 in the vicinity of the plurality of diamond-shaped openings 140.This recessed portion 194 further increases flow through the high flowregion 186.

Although certain trim assemblies and control valves have been describedherein in accordance with the teachings of the present disclosure, thescope of the appended claims is not limited thereto. On the contrary,the claims cover all embodiments of the teachings of this disclosurethat fairly fall within the scope of permissible equivalents.

The invention claimed is:
 1. A fluid valve comprising: a valve bodyhaving a fluid inlet and a fluid outlet connected by a fluid passageway;a trim assembly disposed within the fluid passageway; and a fluidcontrol member movably disposed within the fluid passageway, the fluidcontrol member cooperating with the trim assembly to control fluid flowthrough the fluid passageway; wherein the trim assembly includes a cagehaving a valve seat at one end and a first plurality of diamond-shapedopenings disposed in a wall of the cage, the diamond-shaped openingsextending through the cage perpendicularly to a longitudinal axis of thecage, the plurality of diamond-shaped openings including a first row ofdiamond-shaped openings located adjacent to one another about acircumference of the cage, each diamond-shaped opening in the first rowhaving a longitudinal axis that is parallel to the longitudinal axes ofother diamond-shaped openings in the first row and parallel to thelongitudinal axis of the cage, and a second row of diamond-shapedopenings located adjacent to one another about a circumference of thecage, each diamond-shaped opening in the second row having alongitudinal axis that is parallel to the longitudinal axes of otherdiamond-shaped openings in the second row and parallel to thelongitudinal axis of the cage, the longitudinal axes of thediamond-shaped openings in the first row being offset from thelongitudinal axes of the diamond-shaped openings in the second row,thereby forming a web of material between the diamond-shaped openings,the web of material having a first leg, a second leg, a third leg, and afourth leg that intersect at a center portion.
 2. The fluid valve ofclaim 1, wherein the cage includes a second plurality of openings, atleast one opening in the second plurality of openings having a shapeother than a diamond-shape.
 3. The fluid valve of claim 2, wherein theat least one opening in the second plurality of openings is circular inshape.
 4. The fluid valve of claim 2, wherein the at least one openingin the second plurality of openings is arranged closer to the valve seatthan the first plurality of openings.
 5. The fluid valve of claim 4,wherein fluid flows through the second plurality of openings duringnormal system demand.
 6. The fluid valve of claim 4, wherein fluid flowsthrough both the first plurality of openings and the second plurality ofopenings during a surge condition.
 7. The fluid valve of claim 2,wherein the first plurality of openings defines a high flow region andthe second plurality of openings defines a flow characterizing region.8. The fluid valve of claim 1, wherein at least one opening in the firstplurality of openings includes a first portion and a second portion, thefirst portion having a first edge and a second edge, the first edge andthe second edge forming a first intersection.
 9. The fluid valve ofclaim 8, wherein the intersection includes an angle in the range ofapproximately 10 degrees to approximately 80 degrees.
 10. The fluidvalve of claim 8, wherein the second portion includes a third edge and afourth edge forming a second intersection.
 11. The fluid valve of claim10, wherein the first edge and the third edge are joined by a flatsegment that is substantially parallel to a longitudinal axis of theopening.
 12. The fluid valve of claim 1, wherein the plurality ofdiamond-shaped openings further comprises a third row of diamond-shapedopenings located adjacent to one another about a circumference of thecage, each diamond-shaped opening in the third row having a longitudinalaxis that is parallel to the longitudinal axes of other diamond-shapedopenings in the third row, parallel to the longitudinal axes of thediamond-shaped openings in the first row, and parallel to thelongitudinal axis of the cage, while being offset from the longitudinalaxes of the diamond-shaped openings in the second row.
 13. A cage for acontrol valve trim assembly, the cage comprising: a cage body having anopening at one end and a wall extending from the opening; and aplurality of diamond-shaped openings disposed in the wall, wherein thediamond-shaped openings extend through the wall perpendicular to alongitudinal axis of the cage body, the plurality of diamond-shapedopenings including a first row of diamond-shaped openings locatedadjacent to one another about a circumference of the cage body, eachdiamond-shaped opening in the first row having a longitudinal axis thatis parallel to the longitudinal axes of other diamond-shaped openings inthe first row and parallel to the longitudinal axis of the cage body,and a second row of diamond-shaped openings located adjacent to oneanother about a circumference of the cage body, each diamond-shapedopening in the second row having a longitudinal axis that is parallel tothe longitudinal axes of other diamond-shaped openings in the second rowand parallel to the longitudinal axis of the cage body, the longitudinalaxes of the diamond-shaped openings in the first row being offset fromthe longitudinal axes of the diamond-shaped openings in the second row,thereby forming a web of material between the diamond-shaped openings,the web of material having a first leg, a second leg, a third leg, and afourth leg that intersect at a center portion.
 14. The cage of claim 13,further comprising a plurality of circular openings.
 15. The cage ofclaim 14, wherein the plurality of diamond-shaped openings is fartherfrom a valve seat than the plurality of circular openings.
 16. The cageof claim 15, wherein the plurality of diamond-shaped openings defines ahigh flow region of the cage and the plurality of circular openingsdefines a flow characterizing region of the cage.